Does every one in the world have cancer cells in their body?

No, your body only contains what scientists call “non-transformed” cells; that is, normal cells that do the things that need to be done to sustain your body. If something happens to the cells of your body that damages it in very specific ways, in particular altering specific genes – which are the chemicals, called DNA, in cells that determine what kind of a cell it is – then in certain conditions the damaged cell can become what scientists called “transformed” and grow by cell division into a tumor. Typically a cell has to take at least two such damaging “hits” to become transformed. Normal cells can undergo cell division also; it is part of normal function for many cells.

For example, your hair grows. But when a cell that isn’t supposed to grow becomes un-controlled and grows without the body’s usual instructions to grow, then you can get a tumor. This then results in cancer.

Scientist

Andrew Yen

Professor of Pathology, Director of Graduate Studies in Environmental Toxicology